In a campaign-style speech at a university in Glenside, Pa., Monday, the president exhorted wavering Democratic lawmakers to enact reform and rejected arguments that the timing is wrong, given the weak economy.

“If not now, when? If not us, who?” Mr. Obama said, calling the status quo “unsustainable” for the nation. “Think about it: We've been talking about healthcare for nearly a century. I'm reading a biography of Teddy Roosevelt right now. He was talking about it, Teddy Roosevelt.”

Obama acknowledged the heavy political lift involved – trying to gain passage of a bill that a majority of Americans do not like or even necessarily understand. But, he said, he will push to pass reform regardless of the political consequences.

“I don’t know how passing healthcare will play politically, but I do know that it’s the right thing to do,” the president said in his speech at Arcadia University, which is in the Philadelphia area.

Opponents of reform are also pulling out the heavy artillery. A conservative group called the American Future Fund launched a TV ad campaign in the districts of 18 Democratic House members, reportedly at a cost of $900,000. All 18 members voted for reform last November; 11 represent districts won by Republican presidential nominee John McCain in 2008. As the November midterm elections draw nearer, those are among the most endangered Democrats.

The Senate version also contains language on abortion that some House Democrats find unacceptable – language that could kill the whole deal. On Sunday, Rep. Bart Stupak (D) of Michigan, an ardent opponent of abortion rights, remained a focus of concern for the Democratic leadership. Mr. Stupak voted for the House version of the legislation after insertion of a provision that he believed would guarantee no federal funding of abortions in the reform. He says if he is not satisfied with the final plan, he could take a dozen Democrats with him in voting “no.” Supporters of abortion rights argue that the Stupak language would institute harsher abortion restrictions than currently exist.